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June 14, 2006

Bug That Kills Ash Trees Found in Illinois

by Sam Savage

CHAMPAIGN, Ill. -- A pest blamed for killing millions of trees across the Midwest has reached Illinois, prompting state officials to prepare a detection and eradication plan they expect to begin within the next few weeks, the state agriculture department said Tuesday.

The emerald ash borer, which feeds on the leaves and wood of ash trees, was found recently by a homeowner in a rural subdivision near Lily Lake, about 40 miles west of Chicago in central Kane County, said Warren Goetsch, division manager for natural resources in the agriculture department. But it's possible the pest has been in trees there as long as five years and has spread.

"I think if it gets established, it will absolutely eliminate all of our ash trees," said James A. Appleby, a University of Illinois professor and scientist with the Illinois Natural History Survey in Champaign. "So far, there are no ash trees that have been found resistant."

The ash borer is blamed for the loss of nearly 20 million trees in Indiana, Ohio, Michigan and neighboring Ontario since it was first found near Detroit in 2002. The pest is believed to have found its way from China to the United States in shipping crates, possibly as long as 15 years ago, Appleby said.

State officials plan to conduct a survey in the next few weeks to try to determine whether the bug has spread beyond the subdivision where it was found and to declare it a nuisance, which would allow the state to destroy infested ash trees, Goetsch said.

"Once we have the delimiting survey done, we'll be scheduling a hearing to establish a quarantine, which would allow us to restrict the movement of infested tree material," he said. "The one thing we don't want to do is facilitate the artificial movement of this."

The survey and hearing are expected to be finished by mid-July, Goetsch said.

Congress appropriated $10 million in this year's budget to help prevent, control and eradicate the emerald ash borer, Sen. Dick Durbin, D-Ill., said in a letter to state agriculture director Chuck Hartke. Durbin also wrote Tuesday to Sen. Conrad Burns, R-Mont., chairman of the Senate Appropriations Subcommittee on the Interior, to seek $2.6 million in new money in next year's budget for research and technology to battle the pest.

"Until recently, the country had been fortunate that the emerald ash borer infestation was bounded to the north, east, and west by three of the Great Lakes, which had helped facilitate mitigation efforts," Durbin wrote. "However, we see with the spread of the emerald ash borer west into Illinois recently, additional funding for EAB research is essential not only to contain the pest, but begin to suppress it."

It's likely the borer reached Kane County in firewood from an infested area, Goetsch said. Besides the yard where it was discovered, state inspectors found at least six more infested trees within five blocks, as well as evidence of infestation in an adjacent subdivision.

But Goetsch said it's possible the infestation can be contained.

"It looks like when this subdivision was put in they did diversify the landscape," he said. "We estimate that perhaps only 5 to 10 percent at the most of the trees are ash."

The pest feeds only on ash trees. The dark green larvae feed on the wood under the bark, killing nutrition-conducting cells of the tree, Appleby said.

After metamorphosis, the half-inch adult beetle chews its way out through the tree, leaving behind a hole about one-eighth inch across and shaped like a capital D. The adult then feasts on the tree's leaves.

While insecticide can control the pest in smaller settings, the only way to eradicate the ash borer in forests is to destroy infested trees, Appleby said. Illinois forests contain an estimated 178 million ash trees, he said.

State officials say they will depend on the public to help find the ash borer, much as with the Asian longhorned beetle, which has been nearly eradicated from Chicago and surrounding suburbs.

"The challenge is going to be because this bug is much smaller," Goetsch said.